Lew - been awhile since I installed a Creeper but I don't remember ever splitting the tractor. I never liked trying to man-handle moving the rearend around even with that BIG Crescent Wrench on the draw bar, as they show in the Service Manual.
Amy - one additional thing that could help is once the engine, clutch assembly and rockshaft are removed, then tilt the tractor up on it's tail, make sure it's well stabilized, and then install the Creeper. Much easier than laying on your back, and it will help the gasket and Creeper fall down into place, rather than fall on the floor.
On that "O", seeing it is going to be worth a lot but I like your pricing idea. If this unit does not run, been sitting a long long time, and has the problems you mention, it will likely have other problems as well. I'd go with what Wayne said - offer a Benjamin to haul it away.
Uncle Kraig - Oh Great One Keeper of the Photos - in that pic you posted of the underside of an Original, how come everything is painted up nicely except that return spring and 2 bolts on the drive shaft?